Professor Heng Pan of Missouri University of Science and Technology (Missouri S&T)works in his lab with graduate student Brandon Ludwig, a co-author of a new research study on a low-cost process to manufacture bioresorbable electronics. (Source: Sam O’Keefe/Missouri S&T)

A new technique to laser print with nanoparticles could be the key to developing electronic devices that can be implanted in the human body and then dissolve on their own without need for surgery to remove them, according to a new study from researchers at Missouri University of Science and Technology (Missouri S&T).

A team of engineers led by Heng Pan—assistant professor of mechanical and aerospace engineering at the university—have developed a laser-printing process that processes print-ready zinc nanoparticles for fabricating tiny electronic components, they said. Xian Huang, a professor of biomedical engineering at Tianjin University in China and a former S&T faculty member, also worked on the research.

Bioresorbable electronics—also known as transient electronics—at this time typically require use traditional microchip fabrication methods. Those in turn require costly optical patterning and vacuum deposition processes.

Using laser printing to develop the devices can be far more cost effective, but there has been an issue with this process because the elements it uses, such as zinc and magnesium, are exposed to oxygen, nitrogen, and other materials that can cause adverse interactions, researchers said.

“Laser sintering of zinc nanoparticles typically has issues with oxidation if performed in an ambient environment,” Pan explained to Design News . “In fact, our work is the first demonstration of laser sintering of zinc in an ambient environment without the oxidation issue.”

Pan and his team used a laser to directly transfer and sinter nanoparticles, he said. “Basically, the laser is focused onto nanoparticle films,” he said. “At the focus spot of the laser, nanoparticles could be sintered into functional structures or transferred or printed.”

The process sinters the nanoparticles together using evaporation and condensation, thus avoiding surface oxides. The zinc conductors that result from the process demonstrated high electrical conductivity, mechanical durability, and water dissolvability, Pan said.

“The new method can direct-print patterned zinc conductors on bioresorbable polymers with conductivity close to bulk values,” he said. “And the fabricated patterns on bioresorbable substrate can be readily integrated with high performance electronics.”

Indeed, there are many benefits for patients to use bioresorbable electronics, one of the reasons they are being eyed as the future of medical devices.

“In healthcare, bioresorbable sensors have the potential for post-surgical monitoring of organ, implant, and wound health without the need for a second surgery to remove them,” Pan said.

The technique also can be applied to the development of environmental sensors, he added. Pan and the team published a paper on their work in the journal Advanced Materials .

The team plans to continue their research to print a wider range of bioresorbable materials and to use the developed printing technique to demonstrate devices with more complicated functionalities and geometries, he said.

Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 15 years.

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